Bio H U9: Cell Growth

Rudolf Virchow

First to study cell reproduction and that all cells come from other cells

Cell cycle

regular pattern of growth, DNA duplication, and cell division in eukaryotic cells

Interphase

longest phase of cell cycle, where cell grows. DNA and organelles are copied and grows more

G1 (Gap 1; Gap=growth)

Carries out normal functions; making proteins

Synthesis (S)

Copy DNA (chromosomes are duplicated)

G2 (Gap 2)

Organelles replicate, preparing for mitosis

Mitosis

create two genetically identical daughter cells with the same number of chromosomes as parent cells

Chromosome

tightly condensed structure made of DNA and proteins

histones

protein DNA coils around

Nucleosome

segment of DNA wrapped around 8 histones

coil/supercoil

increasingly more complex tightly-packed DNA

chromatin

loosely packed mass of DNA and proteins (TYPICAL form of DNA in nucleus)

Chromatid

half a duplicated chromosome

sister chromosome

two halves of a duplicated chromosome (created in S PHASE)

centromere

location where sister chromatids are joined

telomere

end caps of a chromosome (do NOT contain coding, just protect info)

Prophase

Chromatin→chromosomes and Centrioles go to opposite ends. Nucleus membrane and nucleolus disappear

Centrioles

control development and attachment of spindle fibers

Spindle fibers

thin hollow tubes part of cytoskeleton that move chromosomes

Metaphase

Chromosomes line up in the MIDDLE and sprindle fibers attach to centromere

Anaphase

Sister chromatids separate→chromatids. Move to opposite ends

Telophase

• Spindle fibers disappear

• nuclear membrane forms in daughter cells

• chromosomes un co to chromatin

• Nucleus divides (cont. in next phase)

Cytokinesis

division of cytoplasm.

Animal: cleavage furrow forms and cell membrane pinches away

Plant: Cell plate forms in cell and grows out